UBC Faculty Research and Publications

Electrically-activated catheter using polypyrrole actuators: Cycling effects Mirfakhrai, Tissaphern; Shoa, Tina; Fekri, Niloofar; Madden, John D.

Abstract

The effect of cycling on charge-storage, actuation and sensing behavior of a polypyrrole is studied, having its application for an electroactive catheter in mind. It is shown that the electrochemical capacitance of a polypyrrole film decreases by about 15 % over the course of 100 cycles, while the per cycle rate of this decrease drops by 75 % between the first and the last ten cycles, implying that a steady-state value may exist. The decrease in capacitance is shown to have a significant effect on actuation strain. In order to achieve a more constant capacitance and more robust actuation performance, it is proposed to pre-cycle the potential of the film to exhaust the effect of processes that contribute to the decrease in capacitance and allow it to reach a more constant value. The ability of a polypyrrole film to generate currents corresponding to applied external load during actuation is verified and the cycle life time of such a sensor is studied. It is shown that after an initial decrease, the sensor current reaches a steady-state value as well, and maintains that value at least over 5600 cycles. Copyright 2009 Society of Photo-Optical Instrumentation Engineers. One print or electronic copy may be made for personal use only. Systematic reproduction and distribution, duplication of any material in this paper for a fee or for commercial purposes, or modification of the content of the paper are prohibited.

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